Should the 35-year-old make an appearance in a game, he would become the first openly gay player in any of the four major North American team sports.
The 7-footer was expected to play later Sunday against the Los Angeles Lakers.
He revealed his sexual orientation in an April Sports Illustrated article.
"The decision to sign Jason was a basketball decision," Nets General Manager Billy King said in a statement. "We needed to increase our depth inside, and with his experience and size, we felt he was the right choice for a 10-day contract."
Collins, who played for the New Jersey Nets from 2001-08, has averaged 3.6 points and 3.8 rebounds in 713 career games.